Compressor muffler construction and method for muffling compressor discharge gases



July 6, 1965 K. M. GERTEIS 3,193,193

COMPRESSOR MUFFLER CONSTRUCTION AND METHOD FOR MUFFLING COMPRESSOR DISCHARGE GASES 2 Sheets-Shet 1 Original Filed March-13, 1958 FIG 3 FIG. I

INVENTOR.

KAR L M. GERTEIS.

ATTORNE Y.

July 6,, 1965 K. M. GERTEIS 3,193,193

COMPRESSOR MUFFLER CONSTRUCTION AND METHOD FOR MUFFLING COMPRESSOR DISCHARGE GASES Original Filed March 13, 1958 2 Sheets-Sheet 2 FIG? KARL M. GERTEIS. BY

INVENTOR.

ATTORNEY.

United States Patent Ofitice 3,193,193 Patented July 6, 1965 3,193,193 CUMPRESSOR MUFFLER CONSTRUClil-EGN AND METHGD FUR MUFFLING CUE/IPRESSOR DIS- CHARGE GASES Karl M. Gerteis, Cazenovia, N.Y., assignor to Carrier Corporation, Syracuse, N.Y., a corporation of Eeiaware Original application Mar. 13, 1958, Ser. No. 721,227, now Patent No. 3,199,584, dated Nov. 5, 1963. Divided and this appiication Ian. 16, 1963, Scr. No. 251,8h7 4 Claims. (Cl. 230-232) This application is a division of my copending application Serial No. 721,227, filed March 13, 1958, entitled Compressor Muffler Construction and Method for Muffiing Compressor Discharge Gases, now Patent No. 3,109,584 and relates to reciprocating compressors having mufiler constructions for discharge gases. This invention also relates to a method of mufiling the discharge gases of a compressor.

Compressors, and especially compressors in refrigeration systems, are steady sources of sound energy, a portion of which appears as sound waves transmitted from the discharge section of the compressor. 7 This sound energy appears both as kinetic energy and potential energy. The kinetic energy is the result of an instantaneous velocity of slugs or pulsations of gas, and the potential energy is in the form of stored energy manifesting itself in the vibration of any elastic enclosing elements.

In a refrigeration system these sound waves generally originate from the discharge line and the condenser of the refrigeration system associated with the compressor. These sound waves give rise to airborne noises which emanate from the containing walls holding the gas which are caused to vibrate. These noises are initially created by the pulsating nature of the gas supplied by the reciprocating compressor. These streams of gas in the form of pulsations, are followed by low pressure conditions which cause a reverse flow of the gas creating a standing wave which is intercepted by the. next pulsation causing a substantial level of noise. This sound is then conducted through the containing walls and becomes airborne. Simultaneously the energy generated by the collision of gas slugs causes vibration of the containing walls causing further airborne noise.

The present invention envisions solving this problem by the provision of a structure whereby airborne noise is minimized and the pulsating nature of the gas discharge from the compressor is diminished in an inexpensive manner with a minimum pressure drop through the'mufiing element.

The chief object of the present invention is to provide a construction which diminishes the noise resulting from the pulsating nature of the discharge of reciprocating compressors, with a minimum pressure drop and in a manner whereby the discharge line of the compressor is not a Significant source of airborne noise.

- Another object of the invention is to provide an inexpensive cast iron mufiier structure to be bolted to the compressor block.

A further object is to provide an integral muiller which is bolted with the head of the compressor to the compressor block.

A further object is to provide a method for substantially mufiling the discharge gas from a reciprocating compressor with a minimum pressure drop and in a manner whereby the discharge line from the compressor is not a significant source of airborne noise.

A still further object is to provide a cast mufiler for a reciprocating compressor providing a low pass acoustical filter which absorbs vibration causing noises and simultaneously subjects the gases passing therethrough to a minimum pressure drop. These and other objects of the i invention will become more apparent from the following description.

This invention relates to a reciprocating compressor comprising a plurality of cylinders, having a plurality of cylinder heads associated therewith and a manifold placing said cylinders in communication, said manifold being located in the compressor block. Means defining a discharge gas opening is placed in communication with the manifold and a cast mufiler is bolted to the compressor block and connected to said discharge gas opening. The mufl'ler includes first, second and third spaces connected by suitable venturis, thereby constituting an coustical low pass filter.

This invention also relates to a method for mufiling the discharge gases from a reciprocating compressor which consists in the steps of expanding the gas in a first space, passing the gas through a first venturi, expanding the gas in a second space, passing the gas through a second venturi and then expanding the gas in a third space to substantially remove the pulsating nature of the gas.

The attached drawings illustrate preferred embodiments of the invention in which FIGURE 1 is a side view of the compressor incorporating the present invention,

FIGURE 2 is an end view of the compressor shown in FIGURE 1, partially in section to illustrate the cylinder and manifold orientation,

FIGURE 3 is an enlarged sectional view taken along the line 3-3 in FIGURE 1,

FIGURE 4 is a sectional view taken along the line 44 in FIGURE 3,

FIGURE 5 is a side view of a compressor incorporating another embodiment of the invention,

FIGURE 6 is an end view of FlGURE 5, partially in section to illustrate the cylinder and manifold orientation,

FIGURE 7 is an enlarged sectional view taken along the line 77 in FIGURE 5, and

FIGURE 8 is a sectional view taken along the line 8-8 in FIGURE 7.

Referring to the drawings there is shown in FIGURE 1 a side view of a hermetic compressor having a W cylinder orientation. The compressor comprises a compressor block 2 having a motor housing section 3 and a compression equipment section 4. Located at the side of the compressor is a juncture box 5 which is provided to supply electric current to the motor of the compressor. In the lower portion of the compression section of the block is located an access opening having a cover 6. At the upper portion of the compressor is located a mufiler 7 which will be described more fully hereinafter.

FIGURE 2 illustrates an end view of the compressor shown in FIGURE 1 having a section thereof removed to disclose the inner sections of the compressor comprising a portion of the present invention. FIGURE 2 illustrates the W configuration of the cylinders i It and 12. Located in these particular cylinders are the pistons 13, 14 and 15. It will be appreciated that if desired, each section of the W may comprise a plurality of cylinders.

Located above the cylinder Id, is a cylinder head 17, and above the cylinder 12, the cylinder head 18. The cylinder heads 1'7 and 18 are similar in shape. Located above the cylinder 11 is the cylinder head 19 which diilers from the cylinder beds 17 and iii in that the upper portion of the cylinder head 19 is provided with a sealing surface adapted to engage the muliler 7 in sealing contact. The muffler and the cylinder head are attached by suitable bolt connections to the compressor block 2, these bolts being fitted into recesses in the muffier, passing therethrough and engaging threaded portions in the compressor block.

Valve assemblies 29, 21 and 22 are disposed between the cylinder heads and the cylinders. These Valve assemblies function in a well known manner whereby suction gas may be introduced into the cylinder and then the compressed gas is discharged through the valve assembly into the cylinder heads to be ultimately discharged from the compressor.

The valve assembly 21) located below the cylinder head 17 is provided with a suitable opening 23 and the valve assembly 22 located below cylinder head 18 is provided with a similar opening 24. These openings place the cylinder heads 17 and 18 into communication with the manifold construction provided integrally in the compressor block. These manifold sections 25 and 26, respectively, place the cylinder heads 17 and 18 into communication by means of the openings 27 and 28 in the valve assembly 21 with the cylinder head 19. Compressed refrigerant gas in cylinder 11 is discharged through the valve plate 21 into the cylinder head 19 and joins the gases from the cylinder heads 17 and 18.

These gases are then discharged through the opening 30 in the cylinder head 19 into the rnufi'ler 7. FIG- URE 3 is an enlarged sectional view of the mufiier taken along the line 3-3 shown in FIGURE 1. It is noted that the mutller 7 has a general elliptical profile substantially the same as the elliptical profile of the cylinder head 19. This elliptical profile provides the outer wall 32 of the mufller. It will be noted that this elliptical wall has a general undulating interior surface which is the result of the provisions made for bolt holes 33 passing through the muffier body.

FIGURE 4 illustrates a sectional view of one of the bolt sections taken along the line 4-4 in FIGURE 3. It will be noted that the mufiier 7 is provided with a recessed portion 35 into which is placed the head of the bolt 40. The bolt 40 passes through the cylinder head 19, the valve plate 21, and is adapted to engage the compressor block 3. Suitable sealing gaskets 36, 37 and 38 are placed between the elements. By this type connection the valve plate, cylinder head and muifier are attached to the compressor block.

Referring again to FIGURE 3, it will be noted that a partition 42 defines a first space 43 into which the opening 30 in the cylinder head 19 discharges. In the partition 42 there is located an orifice 44 having a general venturi shape which is defined generally by the walls 45. A venturi as used herein consists of means defining a short passage with flaring ends and a constricted connccting opening. The partition 42 and the outer wall 32 combine with a second partition 47 to form a second space 48. Located in the second partition is a second orifice 49 having a general venturi shape generally defined by the walls 50. This venturi discharges into a third space 51 which is located at the opposite end of the muffler from the space 43. The mufiier 7 is provided with a discharge opening 52. Because of symmetry and the need for adequate bolting to unite the mufiier to the compressor body it is necessary to provide a suitable member 53 in the discharge opening 52. This member 53 is provided with an opening therein for a bolt to pass therethrough. It will be noted that this member has a general tear drop shape so as to afford a minimum resistance to the gases passing through the opening 52. For reasons to be disclosed hereinafter the mufiler 7 is cast and is fabricated preferably of cast iron.

FIGURE discloses another embodiment of the present invention. The compressor illustrated is of a V cylinder type comprising a compressor block 611 having a motor section 61 and a compression section 62, suction gas being introduced from the suction gas inlet 63 on the motor side of the block. On the side of the compressor is located a juncture box for making the electrical connections to the motor of the compressor. At the lower area of the compression section is located an access opening having a cover 65; located in the upper portion of the compression section is the mufiler 66.

FIGURE 6 shows an end view of the compressor illustrated in FIGURE 5 wherein a portion is shown in section to disclose the cylinder and manifold orientation. The compressor comprises the cylinders and 71 and as mentioned before a plurality of cylinders may be used in each side of the V. Located above the cylinders are the valve assemblies 72 and 73 and located above these valve assemblies are the cylinder heads 74 and 75.

In a manner similar to that utilized in the previous embodiment the valve plate assemblies 72 and 73 are provided with openings 72' and 73' which place the cylinder heads 74 and 75 into communication with the manifold sections 76 and 77. These maniffold sections meet at a central portion of the cylinder block and are in communication with the discharge opening 78. The mufiler 66 is shown bolted to the compressor and is connected to the discharge gas opening '78.

Referring to FIGURE 7 there is shown a sectional view of the muffler used in FIGURE 5 taken along the line 77. The mufiler comprises a generally cylindrical member 2511 including an internal partition section 81 having enlarged portions to provide space for the bolt openings 82. The partition 81 defines a first space 84 which is connected to the compressor by means of the discharge gas opening '78.

At one end of the muffler, the partition 81 and the housing define a second space 85 which is placed in communication with the first space 84 by means of a venturi 83. This second space is placed in communication with a third space 89, located at the opposite end of the mufiier by means of the venturis 87 and 88 which are defined by portions of the partition 81 and the housing 80 and are located in a parallel relationship on either side of the partition 81. The third space discharges through the discharge opening 90.

The mufiier 66 is attached to the compressor by means of suitable bolts passing through the openings 82 shown in FIGURE 7. FIGURE 8 shows a sectional view of one of the bolt connections taken along the line 8--8 shown in FIGURE 7. This sectional view shows a recessed portion 91 located in the muflier 66. The bolt 92 is passed through the mufiler body and engages the compressor block 60. Located between the compressor block and the mufller is a suitable gasket 93 to insure good sealing engagement between the muffler and the body of the compressor.

Considering the operation of the present invention, referring to the embodiment shown in FIGURES l, 2 and 3, gases compressed in the cylinders 10, 11 and 12 discharge through the various valve plates in a conventional manner and then pass into the cylinder heads 17, 18 and 19. The gases in the cylinder heads 17 and 18 pass through the openings 23 and 24 in the valve plate assemblies. The gas is then passed through the manifold sections 25 and 26 and through the openings 27 and 28 in the valve plate 21. Simultaneously the cylinder 11 discharges through the valve plate 21 into the cylinder head 19. It will be noted at this point that the discharge gases from all these cylinders ultimately pass into the cylinder head 19. The gas is then passed through the discharge opening in the cylinder head 19 and referring to FIGURE 3, the gas passes upwardly into the inufiier 7 in a surge reflecting the pulsating nature of the gas supply from the various cylinders. This surge of gas is then expanded in the first space 43. It will be appreciated at this point that because the mufiier is so close to the source of the pulsating gas there is little opportunity to create airborne noises. The pulsating gas as it enters the first space 43 is suitably expanded and because the cast iron construction provides heavy retaining walls there is little transmittal of vibration through the muffler body itself. The sound is substantially dampened. The discharge gases in the first space 43 are then discharged through the first venturi 44 into the second space 48. The venturi shape of the orifice provides an extremely eflicient discharge opening and causes a diffusion action into the second space. This same action is then repeated through the second venturi 49, into third space 51. At this point the pulsating character of the gases has been suitably diminished. The gas is then discharged through the opening 52 and into the discharge line of the refrigeration system.

The mufiler construction in FIGURE 3 is a form of an acoustical low pass filter. The spaces 43, 48 and 51 provide an acoustical capacitance which is equivalent to an electrical analogy of an electrical capacitance and the venturis create an inertance which is acoustically equivalent to an electrical inductance. This acoustical mufiiing system is substantially equivalent to its electrical analogy of a low pass filter.

The surging gas as it enters the first space is subjected to the acoustical capacitance wherein the gases are expanded therein. The gas is then passed through the inertance wherein the pulsating nature of the gas is diminished.

It will be noted, at this point, that it is normally suggested that an orifice be used as an inertance. However, it has been found that a venturi shaped orifice is more efiicient in this application because of the lesser amount of energy expended passing gases through an orifice of this shape. The gas entering the venturi is first accelerated and then diffused into the next space. Furthermore, the pressure differential occurring across the venturi is such that the venturi acts as a check valve. As previously mentioned, one of the sources of noise in a compressor is the phenomenon that behind the surge of gas there is created a low pressure condition causing a standing wave which is intercepted by the next surge of gas causing a substantial amount of noise. By passing the gas into the first space and expanding therein, then passing the gas into the venturi, a large amount of the initial surge is lost. Because of the check valve action of the venturi, the effects of this standing wave interception phenomenon are greatly diminished. The gases discharged into the second space 48 are again expanded and then pass through the second venturi 49 until finally in the third space-51 the pulsating nature of the gas is substantially lost. It will be appreciated that because of the cast iron construction there is little opportunity for vibration of the containing body of the muffler thereby diminishing the possibility of airborne noise. The gases passing into the discharge line connected to the discharge opening 52 have had most of the sound producing energy intercepted.

Referring to the second embodiment comprising the FIGURES 5, 6 and 7 gas is compressed in the cylinders 70 and 71 and discharged into the cylinder heads 74 and 75. This gas is directed through the openings 72 and 73 in the valve assemblies and is then passed through the manifold passages 76 and 77 located within the compressor block. These discharge gases are then passed through the opening 78 into the muflier 66. This action is essentially similar to that which occurred in the initial embodiment disclosed. However, the gases are not passed from the manifold into another cylinder head but rather directly into the mufiier 66.

Referring to FIGURE 7, the gas is passed into the first space 84 where it is expanded and then passed through the venturi 83 into the second space 85. From the second space the gas is passed through the venturis 87 and 88 which act as an inertance to the sound and the gas is directed into the third space 89 and discharged through the opening 90 from the mufiier. The sound dampening features of this particular mufiier are essentially the same as those disclosed in FIGURE 3 with the exception that the path of the gases is different since the direction of the gas is changed 180 and also as the gas passes from the second space to the third space, it encounters two venturis before the gas passes into the third space 89.

The present invention provides an inexpensive and highly effective manner for dampening and absorbing the 6 kinetic and potential energy which originates from the compressor and finds its way into sound energy. The pulsating nature of the gas is intercepted at the earliest opportunity and because of the special acoustical low pass filter construction incorporating the unique venturis, a highly efficient muffler is provided which not only deadens the sound but also subjects the gas to a lesser pressure drop than is normally encountered. The extremely close proximity of the mufiler to the source of the sound furthermore diminishes the amount of airborne noise which is passed from the compressor and furthermore as a result of the cast iron construction of the muiiier, the mufiler itself is an insignificant source of vibration thereby providing a highly compact and inexpensive muffler construction.

While I have described the preferred embodiment of the invention it will be understood that the invention is not limited thereto so that it may be otherwise embodied in the scope of the following claims.

I claim:

1. In a reciprocating compressor, the combination of a compressor block, a plurality of cylinders in said block, a plurality of cylinder heads associated with said cylinders (forming spaces to receive compressed gas discharged from said cylinders, means defining a manifold in said block placing the discharged gas spaces in communication with one another, means defining a discharge gas opening in communication with said manifold, a cast muffler open on an end attached to said block and connected to the means defining said discharge gas opening, said mufiier having a partition therein, the walls of said mufiler and said partition cooperating to define a first mufiler space in communication with and in close proximity to said discharge gas opening and a second muffler space remote from said discharge gas opening and an orifice connecting said discharge gas opening and said first muiller space, said second space being connected to the first space by means including two venturis in parallel through which discharge gas is passed in a direction opposite to the gas passing through the orifice whereby the discharge gases introduced into the mufiier are discharged through the orifice and expanded into the first space, discharged through said venturis and expanded again in the second space to substantially diminish the pulsating nature of the gas.

2. In a reciprocating compressor, the combination of a compressor block, a plurality of cylinders, a plurality of cylinder heads associated with said cylinders forming spaces to receive compressed gas discharged from the cylinders, means placing said compressed gas spaces into communication; said compressor block having a discharge gas opening therein in communication with said means placing said compressed gas spaces in communication, a cast muflier attached to said compressor block and connected to said discharge gas opening, said mufiier comprising means defining a first muffler space, means delining a second muffler space, means defining a third mufiler space, said first mufiler space being located between said second and third muffler spaces, a first venturi placing said first and second muifier spaces in communication and second and third venturis placing said second and third mufiler spaces into communication, said second and third venturis being located on opposite sides of said first muffier space, said first mufiier space communicating with said discharge gas opening.

3. A cast mufiler for a reciprocating compressor comprising a body member having a general cylindrical shape, a center partition member fully enveloped by said body member, said partition member enclosing a first space adapted to communicate with a discharge opening in said reciprocating compressor, means for introducing discharge gas into the first space, a venturi located in said partition member, said partition member defining with said body a second space into which said first venturi discharges, said partition defining with said body a third space and also a first and a second venturi placing said second and third spaces into communication, said vcnturis being located on opposite sides of said partition member, and being oriented so that gas passing through the first venturi will pass in the opposite direction through said second and third venturis and means for discharging gas from said third space.

4. A cast muffler for a reciprocating compressor comprising a body member having a general oblong shape and defining a chamber, said body member being adapted to be secured in sealing engagement with said reciprocating compressor, a partition member located in said chamher and defining a first space, said partition member with said body member substantially dividing the chamber into second and third spaces, a portion of said partition member defining a first venturi placing said first and second spaces into communication, said body member and said partition member defining second and third venturis, each of said second and third venturis placing the second and third spaces into communication, said venturis being 8 formed on opposite sides of the partition member, means for passing discharge gas from a reciprocating compressor directly into the first space and means for discharging the discharge gas from the third space.

References Cited by the Examiner UNITED STATES PATENTS 1,490,957 4/24 Birger l81'-36 X 1,757, 85 5 5/30 Chilowski. 2,576,876 11/51 Gamble 230-47 X 2,853,229 9/58 Dolz 230236 X 3,031,026 4/62 Price 181-36 X FOREIGN PATENTS 595,221 7/25 France.

KARL J. ALBRECHT, Primary Examiner.

LAURENCE V. EFNER, JOSEPH H. BRANSON, JR.,

Examiners. 

1.IN A RECIPROCATING COMPRESSOR, THE COMBINATION OF A COMPRESSOR BLOCK, A PLURALITY OF CYLINDERS IN SAID BLOCK, A PLURALITY OF CYLINDER HEADS ASSOCIATED WITH SAID CYLINDERS FORMING SPACES TO RECEIVE COMPRESSED GAS DISCHARGED FROM SAID CYLINDERS, MEANS DEFINING A MANIFOLD IN SAID BLOCK PLACING THE DISCHARGED GAS SPACES IN COMMUNICATION WITH ONE ANOTHER, MEANS DEFINING A DISCHARGE GAS OPENING IN COMMUNICATION WITH SAID MANIFOLD, A CAST MUFFLER OPEN ON AN END ATTACHED TO SAID BLOCK AND CONNECTED TO THE MEANS DEFINING SAID DISCHARGE GAS OPENING, SAID MUFFLER HAVING A PARTITION THEREIN, THE WALLS OF SAID MUFFLER AND SAID PARTITION COOPERATING TO DEFINE A FIRST MUFFLER SPACE IN COMMUNICATION WITH AND IN CLOSE PROXIMITY TO SAID DISCHARGE GAS OPENING AND A SECOND MUFFLER SPACE REMOTE FROM SAID DISCHARGE GAS OPENING AND AN ORIFICE CONNECTING 